Developmental-Regulatory Aspects of Brain Tryptophan Hydroxylase

Abstract

Several articles in this volume deal with the roles of serotonin and other neurohumoral substances in the regulation of neurogenesis. It should be emphasized that the maturation of the serotonergic system itself must also be subjected to regulation by a variety of biochemical events. In our laboratory, we are concerned with the developmental regulation of tryptophan hydroxylase (TPH), the enzyme that catalyzes the initial and probably rate-limiting step in the biosynthesis of serotonin from tryptophan. Two regulatory aspects are described in this article. One involves adrenal glucocorticoids as a regulatory factor for the enzyme during postnatal development of the brain. The other involves the activation of the enzyme by ATP-magnesium and its developmental relevance. Some of the unpublished experiments summarized here were conducted in collaboration with my energetic colleagues, Tom Lysz, Andy Towle, and Ralph F. Alderson. Their contribution to the overall work was no less important than mine.